This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
| n | a(n) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 920 |
| 6 | 17760 |
| 7 | 122640 |
| 8 | 537040 |
| 9 | 1794240 |
| 10 | 4994640 |
| 11 | 12178320 |
| 12 | 26840880 |
| 13 | 54620280 |
| 14 | 104184080 |
| 15 | 188348160 |
| 16 | 325459680 |
| 17 | 541078720 |
| 18 | 869994720 |
| 19 | 1358615520 |
| 20 | 2067768480 |
| 21 | 3075954840 |
| 22 | 4483100160 |
| 23 | 6414845360 |
| 24 | 9027424560 |
| 25 | 12513177600 |
| 26 | 17106746800 |
| 27 | 23092009200 |